Genetic variation in Eucalyptus camaldulensis Dehnh. for growth and stem straightness in a provenance–family trial on saltland in Pakistan

Abstract

In an Eucalyptus camaldulensis Dehnh. provenance–family trial established on a moderately saline–sodic site in Pakistan, 114 families (from 14 Australian provenances) and six Pakistani seedlots were evaluated for survival, growth and stem form, up to the age of 60 months. Significant differences were found among provenances and families-within-provenances for all parameters. The provenance from De Grey river (WA) performed best, with 18 of the 25 families having very fast growth rates. Overall survival, at 60 months, was 74% (provenance mean range of 89% (Wiluna) to 28% (Vic.)). Overall mean height at age 60 months was 8.7 m (provenance mean range of 10.2 m (De Grey river) to 4.6 m (Vic.)). Overall mean diameter at breast height (DBH) was 6.7 cm with provenance mean range from 9.2 cm (De Grey river) to 3.4 cm (Vic.). Stem straightness (scored qualitatively on a four point scale of 1–4 with four as the straightest stem) for most of the provenances was good to very good with a trial mean value of 3.2. Within-provenance individual tree heritability estimates obtained for height, DBH and stem straightness at age 60 months were 0.14, 0.11 and 0.15, respectively (assuming a coefficient of relationship of 0.3 for open-pollinated families of E. camaldulensis). Covariate analyses showed that variations in soil salinity across the trial site had little influence on comparison between means of provenances or of families-within-provenances. Based on this experiment, we believe that there is good potential to genetically improve growth of E. camaldulensis in breeding programs for saline soils in Pakistan.